208 PHILOSOPHICAL TRANSACTIONS. [^ANNO 1792. 



rod ; excepting a few times, in very moist weather, in which it was obtained by 

 the hand-exploring rod, with a lighted torch to it. 



Times. Times. Days. 



''\'':^l^X'mt } '-''"^ '' ^'^Sative 27 Sparks drawn 13 



June Positive 45 Negative 22 Sparks drawn 5 



July Positive 36" Negative 23 Sparks drawn 8 



August Positive 33 Negative 6 Sparks drawn 3 



September Positive 39 Negative 11 Sparks drawn 19 



October Positive 37 Negative 7 Sparks drawn 22 



November Positive 30 Negative 8 Sparks drawn 1 1 



December Positive 35 Negative 11 Sparks drawn 6" 



January Positive 28 Negative 8 Sparks drawn 3 



February Positive 36 Negative 12 Sparks drawn 6 



March Positive 3+ Negative 8 Sparks drawn 2 



April Positive 30 Negative 1 4 Sparks drawn 8 



423 times 157 times 106 days. 



It appears, by comparing the monthly account of this year with that of the 

 preceding, that there has been a considerable disproportion in the electrical posi- 

 tive state of the atmosphere ; but which, when duly weighed, will not appear so 

 very great as it now does. For when it is considered, that in the preceding year 

 there were 73 days in which weak signs only of the electric fluid were observed ; 

 that 7 days were destitute of electric signs ; and that that kind of weather in which 

 very weak signs of atmospherical electricity could be obtained, is now found, by 

 a more sensible electrometer than was at that tirne used, to be always positively 

 electrified, it will, he presumes, diminish the apparent disproportion. And as 

 for the remaining difference, he also attributes a good deal of it to the accuracy 

 of his present mode of obtaining atmospherical electricity, with a more complete 

 apparatus ; by which he has been able to collect the electric fluid, in sufficient 

 quantity to ascertain the kind which predominates in the atmosphere, even in its 

 weakest state. 



From repeated observations, and long experience, Mr. B. is perfectly satisfied 

 that the aqueous vapours, suspended in the air, are constantly electrified ; re- 

 quiring only the aid of a proper collector, to render the effects of their electricity 

 at all times sensible. And for this reason, there may be justly said to be an 

 electrical atmosphere within our aerial atmosphere. During a course of mode- 

 rate weather, the electricity of the atmosphere is invariably [)ositive ; and exhibits 

 a flux and reflux, which generally causes it to increase and decrease twice in every 

 24 hours. The moments of its greatest force are about 2 or 3 hours after the 

 rising, and some time before and after the setting, of the sun ; those when it is 

 we;ikest, are froin mid-day to about 4 o'clock. The periodical electricity of the 

 atmosphere seems to be manifestly influenced by heat and cold. Hence it plainly 

 appears, why we always find warm small rain to be but weakly electrified ; when 

 cold rain, which falls in large drops, is the most intensely electrified of any. 



